Royal mail returned all my mail to sender six weeks after i moved in?

royal mail returned all our mail for six weeks after we moved in to our property we are now left hundreds of pounds in debt and facing eviction because they failed to deliver our housing forms to our address but simply addressed all our mail for six weeks return to sender what are my rights royal mail are bang out of order and nearly lost 6 of us our 4 kids included our home still don't know if were going to be given an eviction notice